Window structure



May 4, 1965 D. c. MUESSEL 3,181,204

WINDOW STRUCTURE Filed Aug. 23, 1963 5 Sheets-Sheet l INVENTOR AA/ /142/55554 www @ZM/Wm Arran/E 5.

5 Sheets-Sheet 2 Filed Aug. 25, 1965 INVENTOR /M/ C. A44/555m Arran/5 5 May 4, 1965 D. c. Mul-:ssx-:L

WINDOW STRUCTURE 5 Sheets-Sheet 5 Filed Aug. 23, 1963 D. c. MuEssEL WINDOW STRUCTURE May 4, 1965 5 Sheets-Sheet 4 Filed Aug. 23, 1965 .NNN RN .RN j QNQN W M M W. W W 1. NN ,M/WC.. c Q QN ?Q IMJ/l. /A N. W. m m www w U.|l.r! IT lvm M ulli, www T mnm m |1. 1 1 l 1 5 Sheets-Sheet 5 May 4, 1965 D. c. MuEssEL.

WINDOW STRUCTURE Filed Aug. 2s, 1963 i .335 :Fl I3 "1g 356 INVENTOR DAA/ C Mc/ESEL BY Arroz/JE 5.

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United States Patent Oiice 3,181,2@4 Patented May 4, 1965 York Filed Aug. 23, 1963, Ser. No. 304,124 2 Claims. (Cl. 20-53) This invention relates to window structures and, more particularly, to a window structure formed of metal building elements and provided with operating sash.

One common commercial version of a window structure includes window frames for insertion into window openings in a building wall. The window frames form sash openings for accommodating fixed or operating window sash. The frame members forming the operating sash openings are provided with two transversely spaced inner and outer sealing areas completely around the perimeter of the sash opening and the operating sash has complementary transversely spaced sealing areas completely around the perimeter thereof cooperatively associated with the sealing areas'of the frame to provide transversely spaced inner and outer seals between the operating sash and the frame. It will be appreciated that with such construction a space is provided completely around the operating sash and between the sash and window frame assemblies. In order to drain any moisture which may be formed within such space, the window has heretofore been provided with drainage openings communicating between the space and the outer surface of the wall. These drainage openings take the form of weep holes either drilled through the sash frame members or formed by voids in the outer seal.

lt will be appreciated that under certain weather conditions, particularly in stormy weather with rain and wind, the inner wall of a building may be at a slight vacuum with reference to the air pressure against the outer wall of the building. Under such conditions the difference in pressure between the inner wall and the outer wall will be carried across the inner seal between the sash and the frame; the weep holes prevent any substantial pressure differential across the outer seal. However, due to water running down the outer surface of the building and clinging to the building by surface or interfacial tension, the rain water may close the drainage openings, forming a cover or liquid membrane across the drainage openings due to the cohesion of the water particles as they pass over the drainage openings. Under the above-described conditions, with a pressure differential between the inner and outer walls of the building, any leakage of air around the inner seal will cause a pressure drop in the space between the operating sash and the window frame. Consequently, rain water will be drawn into this space through the drainage openings and occasionally the accumulation of water in this space is suiiicient to cause the rain water to be drawn through the inner seal and to run down the inner surface of the wall. Of course, such occasional entry of rain water around the operating sash is highly undesirable for obvious reasons.

Accordingly, it is an object of the present invention to provide a new and improved window structure with an operating sash which overcomes the aforementioned difculties.

A further object of the present invention is to provide a new and improved window structure having operating sash which minimizes the leakage of rain water around the sash.

A further object of the present invention is to provide a new and improved window structure of the type having an operating sash wherein leakage of water around the sash is minimized under adverse conditions in which the inner wall of the building is at a vacuum relative to the air pressure on the outer wall of the building.

A further object of the present invention is to provide a new and improved window structure.

Further objects and advantages of the present invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

ln accordance with these and other objects, there is provided an improved window structure of the type having operable window sash. The window structure includes a window frame formed of interconnected frame members to provide sash openings for the operable window sash. The frame members forming sash openings are provided with inner and outer transversely spaced seal portions; the inner seal portion extending entirely around the perimeter of the opening. The sash is formed of interconnected sash members forming a sash frame to hold the glass or other window panel, and each provided with inner and outer transversely spaced seal portions respectively cooperating with the inner and outer seal portions of the trarne. The inner seal portion of the sash extends entirely around the perimeter of the sash. The seal portions may carry weather stripping or other gasket means to provide inner and outer transversely spaced Weathertight seals. In this manner there is provided an inner seal entirely around the perimeter of the operating sash, and an outer seal. Means are provided for maintaining the space between the seals at the outside air pressure so that water cannot be sucked into this space and up over the inner seal by vacuum conditions on the inside of the wall. More specifically, in a preferred embodiment, the outer lower portion of the outer seal is omitted to provide a longitudinal slot or gap entirely across the lower edge of a window to fully exhaust the space between the seals to the outside atmosphere. It has been found that a nominal slot of approximately 1a-inch would prevent the drawing-in of water into the space between the seals since such a slot is quite adequate to prevent a lm or membrane of water forming entirely across the opening which might block the opening. Moreover, an upper outer seal is optional. Any vapor which condenses or otherwise leaks into the space between the sealed portions will run out through theV lower slot and be directed to the outside of the building. Moreover, in the preferred embodiment there is provided a water directing lip on the lower sash member further protecting the slot from water running down the surface of the building and further minimizing the suction or flow of rain water within the -space between the sealed portions.

For a better understanding of the present invention, reference may be had to the accompanying drawings, wherein:

FIG. l is a perspective View of a window structure according to the present invention;

FIG. 2 is a fragmentary cross-sectional view of a prior commercially available window structure illustrating the difficulty which has arisen with such prior structures;

FIG. 3 is a fragmentary cross-sectional View of the window structure of FIG. l, taken along line 3 5 of FIG. 1, illustrated to a larger scale than FIG. 1, and assuming that the operable sash of FIG. 1 is closed;

FIG. 4 is a fragmentary cross-sectional View of the window structure of FIG. 1 takenalong line 4-4 of FIG. 1, illustrated to a larger scale than FIG. l, and assuming that the operable sash of FIG. 1 is closed;

FIG. 5 is a fragmentary cross-sectional view of the window structure of FIG. 1, taken along line 5-5 of FIG. l, illustrated to a larger scale than FIG. 1, and assuming that the operable sash of FIG. l is closed;

FIG. 6 is a fragmentary cross-sectional view of the window structure of FIG. 1, taken along line 66 of FIG. l, illustrated to a larger scale than FIG. l, and

assuming that the operable sash of FIG. l is closed;

FIG. 7 is an elevational view of another window structure according to the present invention;

FIG. 8 is a cross-sectional view of the window structure of FIG. 7 taken along line 8 8 of FIG. 7, and illustrated to a larger scale than FIG. 7;

FIG. 9 is a fragmentary cross-sectional view of the window structure of FIG. 7, taken along line 9 9 of FIG. 7, and illustrated to a larger scale than FIG. 7;

FIG. 10 is an elevational view of yet another window of the present invention;

FIG. 1l is a cross-sectional view of the window structure of FIG. 10, taken along line 11--11 of FIG. 10, and illustrated to a larger scale than FIG. l;

FIG. 12 is a fragmentary cross-sectional view of the window structure of FIG. l0, taken along line 12-12 of FIG. 10, and illustrated to a larger scale than FIG.

FIG. 13 is an elevational view of yet another window structure according to the present invention;

FIG. 14 is a cross-sectional view of the window structure of FIG. 13, taken along line 14-14 of FIG. 13, and illustrated to a larger scale than FIG. 13; and

FIG. l5 is a fragmentary cross-sectional View of the window structure of FIG. 13 taken along line 15-15 of FIG. 13, and illustrated to a larger scale than FIG. 13.

Referring first to the commercially available prior art window structure, fragmentarily illustrated in FIG. 2, the window structure includes an operable window sash 23 positioned within a iixed frame 20. The fixed frame 20 includes a sill member 22 which, with other interconnected components of the frame 29, not shown, form a sash opening for the sash 23. The sash 23 includes a sash frame formed of a plurality of interconnected sash members, only one of which is illustrated in FIG. 2, and suitable sash paneling, such as glass glazing 24, secured in the sash frame by known means. In order to form a substantially weather-tight seal between the sash 23 and the frame 20, there is provided an inner seal 25 and an outer seal 26 each extending entirely around the perimeter of the sash to provide transversely spaced inner and outer seals having a space 27 therebetween. To provide for drainage of any water vapor which collects or otherwise condenses within the space 27, suitable drainage weep means or openings 28 are provided. In the illustrated ernbodiment, the weep means 28 is formed by a weep hole cut in the frame 20 and discharging to the outside of the window so that any moisture which collects within the space 27 is drained to the outside of the wall of the building. Although the drainage means 28 are normally very small, it has been found that slots or gaps in the outer seal 26 forming openings 1s-inch Wide and 3%; inch long are subjected to the difficulties of the prior art windows.

As pointed out above, under certain weather conditions, the inside wall of a building may be at vacuum conditions relative to the air pressure on the outside wall. In such conditions, the difference in air pressure is carried across to the inner seal 25 since the space 27 is exhausted to the outside atmosphere lthrough the weep openings 28. Under such conditions, a small leakage across the inner seal 25 will cause an air flow around the seal as indicated by the arrows 29 and an inward flow of air through the weep openings 28 as indicated by the arrows 30 will be set up. The flow of water down the outside of the wall in wet weather will cause a liquid membrane of water to form over the weep openings 28 due to the cohesion of the water particles, and will plug or seal the weep openings. Such conditions will cause water -to be drawn in through the drainage openings 28 and provide a build-up of water within the space 27. Occasionally, the build-up of water in the space 27 reaches suiiicient proportions to cause water to be sucked into the inside of the building 4 around the inner seal with the air flow indicated by the arrows 29.

It has heretofore been thought that it was necessary to provide better-and-better inner and outer seals in order to avoid this inner seepage of water through the window. It will be appreciated that substantially airtight seals around a window sash are extremely difficult to provide commercially, and, moreover, such seals tend to develop leaks as they age.

It has been discovered, according to the present invention, that any inward seepage of water around the sash may be virtually eliminated by suitably exhausting the space 27 to the atmosphere so as to prevent vacuum conditions from arising within the space 27.

Referring now to the window structure according to the present invention, and particularly to the embodiments of FIGS. l and 3 to 6, there are illustrated a window structure 35 including a fixed window frame 36 and a plurality of window sash including an upper fixed window sash 37; an intermediate operable window sash 38, here illustrated as the projected-out, glazed-out type; and a lower operable window sash 39, here illustrated as a projected-in, glazed-out sash. It will be appreciated that various sash arrangements may be used and, more specifically, the embodiments of FIGS. 7 to 15 illustrate various other sash structures. As viewed in FIG. l, the window structure 35 is illustrated from the inside of the building wall. All of the metallic components of the window structure 35 may suitably be formed of aluminum extrusions, or other suitable material.

In order to provide a suitable frame for the sash, and to provide the means for attaching the window structure 35 to the wall of a building, the window frame 36 is formed of a plurality of interconnected frame members, including vertical frame members 41 and 42, head frame member 43, sill frame member 44, and intermediate frame members and 46. The frame members 41, 42, 43, and 45 form an opening for the fixed sash 37; the frame members 41, 42, 45, and 46 form an opening for the operable sash 38; and the frame members 41, 42, 46, and 44 form an opening for the operable sash 39. Moreover, each of the vertical frame members 41 and 42, head frame member 43, and sill frame member 44 is provided along its outer surface with an outwardly extending ange 41a, 42a, 43a, and 44a to provide for insertion of the window structure 35 into or against a building wall. Each of the frame members 41, 42, 43, 44, 45, and 46 additionally includes a traverse section 41h, 4Zb, 43h, 441;, 45b, and 4Gb.

The fixed sash 37 is formed of glass or other panel material 37a glazed within the sash opening formed by the frame members 41, 42, 43, and 45.

Referring lirst to the operable sash 38, the sash 38 includes a sash frame formed of a plurality of interconnected sash members including the vertical sash members 50 and 51, upper sash member 52, and lower sash member 53; and additionally includes an intermediate muntin or sash member 54, which forms a frame enclosing the glazing panels. The sash members 50, 51, 52, 53, and 54 are appropriately interconnected to enclose glass or other panel means 38a and to fill the sash opening formed by the members 41, 42, 45, and 46.

To provide for forming the lower projected-in, glazedout operable sash 39, the sash includes a sash frame formed of a plurality of vertical sash members and 61, and upper sash member 62, and a lower sash member 63 interconnected to provide a frame enclosing glass or other panel means 39a. The operable sash 39 is adapted to fill the opening provided by the frame members 41, 42, 46, and 44.

In order to provide for operation of the sash 38 and 39 between their open and closed positions, each of the sash 38 and 39 is connected to the frame 36 by suitable sliding hinge blocks 65, FIG. 1, received in a groove 67 (best shown in FIGS. 5 and 6) applied to the vertical frame members li1 and 42, and a hinge leaf dil connected to the respective sash and pivotally mounted to the sliding block 65. Additionally, the sash is connected intermediate its ends to the frame 36 by respective connecting links 69 and 7?, each having one end pivoted to the frame 3d and the other end pivoted to the respective sash 38 and 39. ln this manner, each of the sash 3d and 39 may be opened by the pivoting of the sash about the respective connecting link 69 or 7l) and the simultaneous sliding and pivoting of the sash due to the action of the sliding hinge blocks 65.

In accordance with the present invention, in order to provide an air and watertight closure between each of the sash 38 and 39 relative to the frame 41, each of the sash is provided with an inner seal 72 and 73, respectively, FlGS. 3 to 6, which extends entirely around the perimeter of the sash 33 and 39 along the inner edges thereof to form a complete weather seal around the inner perimeter of the sash. The seals 72 and 73 may be formed of any suitable weather stripping or gasket material. The seals 72 and 73 are as weathertight as can be provided commercially; of course, some air seepage may occur around the seals. The vertical sash members Sti and 51 of the operable sash 33 are provided with outer seals 75 adapted to engage the vertical frame members 41 and 42, and similarly the vertical sash members 6i) and 61 of the operable sash 39 are provided with outer seals 76 adapted to engage the vertical frame members 41 and 42, as illustrated in FlGS. and 6. Accordingly, there is provided around each of the sash 38 and 39 a clearance space 78 and 79, respectively, dened between the transversely spaced inner and outer seals adjacent respective edges of the transverse sections 41h, 42h, 44h, 45h, and Lleb, and which forms a tortuous path between the inside and outside surfaces of the window structure 35 when the sash 3S and 39 are closed. Moreover, in the illustrated embodiment the operable sash 39 is provided with an optional upper outer seal 77 across its upper outer edge.

In accordance with the present invention, the clearance spaces 7S and 79 are provided with a suitable opening which will vent the spaces to the atmosphere and drain any moisture or condensate which may be formed within the spaces and which will prevent the build-up of a vacuum with the spaces 7S and 79. More speciiically, each of the clearance spaces 78 and 79 communicate with the outside atmosphere through respective drainage gaps or slots 81 and 32 which are eiective under all weather conditions fully to exhaust the respective spaces 78 and '79 to the outside atmosphere and thereby to maintain the spaces 7S and 79 at atmospheric pressure at all times. It will be observed that since the spaces 78 and 79 are maintained at outside atmospheric pressure, an upper outer seal optional and, therefore, the operable sash 38 is illustrated as provided with an air channel S3 at the upper outer edge of the sash 3S, while the operable sash 39 is provided with the upper outer seal 77 as explained above. The drainage slots S1 and 32, in the illustrated Vembodiments, are formed in part by an inwardly projecting recess or charnfer idc and 411C, on the upper outer edge of the respective frame members i6 and 44. Moreover, the lower sash members 53 and 63 are provided with downwardly and outwardly projecting water directing lips 53a and 63a to direct rain water and other surface water running down the outer side of the wall away from the respective drainage slots 31 and 32.

Referring now to the operation of the improved window structure according to the present invention, it has been found that by the provision of the drainage slots 81 and S2 extending entirely across the lower outer edge of the sash 38 and 39, respectively, and forming in eifect large weep holes, that any seepage of air iiow around the inner seals 72 and 73 of the respective sash 38 and 39 will cause a iiow of air through the drainage slots 81 and 82. However, water will not be drawn up through the drainage slots 31 and 82 as the slots are of sufficient size that a water membrane will not form thereacross to block the channels. Accordingly, the clearance spaces 78 and 79 are maintained at near outside air pressure at all times so that there is no possibility of rain or other water being sucked into the spaces. The drainage slots 81 and 82 need to be of a sufficient size that the cohesion of the water particles is insufficient to maintain a liquid bridge completely across the respective drainage channels. The pressure within the spaces 78 and 79 therefore remains equalized with the outside ambient pressure at all times. As indicated above, it has been found that weep holes of a size i inch across and 2%; inch long has not been suiiicient to prevent the formation of such membrane. On the other hand, it has been found that drainage slots having a width of lz inch and extending entirely across the bottom of the sash will operate very satisfactorily in preventing the formation of a water membrane which would block the slots and prevent evacuation of the respective spaces 78 and 79 to the outside atmosphere. Of course, it is to be understood that the drainage slots 81 and 82 need not extend entirely across the lower edge of the sash, but that the requirement is that suitably sized openings be provided which will prevent the formation of a membrane entirely across the weep hole or drainage slot which will serve to plug up the slot. The required opening size would vary according to factors such as the material that the window members are formed of and the surface finish of the members.

FIGS. 7 to 9 illustrate a projected-out, glazed-in window structure according to the present invention. Except for the inside glazing to the window panels, the structure and arrangement is similar to the projected-out, glazed-out sash arrangement 38, illustrated in the embodiment of FIGS. 1 and 3 to 6. More specifically, the embodiment of FIGS. 7 to 9 comprises a window structure including a window frame 136 and an operable sash 138, there illustrated as a projected-out, glazed-in arrangement. The window structure 135 is formed of vertical frame members 141 and 142, a head frame member 143, and a sill frame member 144. The frame members are interconnected to form a sash opening. The operable sash 13S is formed of vertical sash members 150, 151, upper sash member 152, and lower sash member 153. The sash 138 is provided with an inner seal 172 extending entirely around the inner perimeter of the window structure to provide an inner seal between the sash 138 and the frame 136. Additionally, the sash 13S is provided with outer seals 175 along its Vertical sash members and 151. As in the embodiment of sash 38, there are no upper or lower outer seals, but a drainage slot 181 is provided at the lower outer edge of the sash 138, and an air channel 133 is provided at the upper outer edge of the sash 13S. The drainage slot is formed by a chamfer 14de formed in the outer upper edge of the frame member 144 and an outwardly and downwardly extending water directing lip 1S3a formed in the lower sash member 153. In this manner a clearance space 173 is provided extending entirely around the sash 133 and communicating with the outside atmosphere through tbe drainage slot 181. Moisture or other condensation formed within the space 178 is directed out through the drainage slot. Moreover, it will be appreciated that in like manner, as heretofore described in connection with the embodiment of FIG. l and FIGS. 3 to 6, no water membrane will form across the drainage slot 181 and, accordingly, entry of water through the sash perimeter will be minimized.

FlGS. l0 to l2 illustrate the application of the present invention to a projected-in, glazed-out window of the type having a double or hollow frame construction. More specifically, FIGS. l() to 12 illustrate a window structure 235' including a window frame 236 and an operable sash 233. 'Ille window frame 236 is formed of a pair of vertical frame members 241 and 242, a head frame member 243, and a sill frame member 244. The operable sash 238 includes vertical sash members 250 and 251, an upper sash member 252 and a lower sash member 253. As illustrated in FIGS. il and 12, the sash members 250, 251, 252, and 253 are of the hollow tubular type and may readily be formed of extruded aluminum or similar material. Moreover, the sash 233 is provided with an inner seal 272 extending entirely around the inner periphery thereof, and is provided with vertical outer seals 27S extending along its vertical edges and an optional upper outer seal 277 extending across its top outer edge. A clearance space 273 is formed entirely around the sash 23S and to accommodate the drainage of moisture which may collect in the clearance space 278, there is provided a drainage slot 281 extending entirely across the lower front edge of the clearance space 278. As heretofore described, the drainage slot 281 is formed between a chamfer 244:1 formed on the upper outer edge of the frame member 244; and an outwardly and downwardly extending water directing lip 25311 formed on the sash member 253. It will be appreciated that, in view of the large cross-sectional area of the drainage slot 281, no liquid membrane can form across the slot to block the slot.

FIGS. 13 to l5 disclose the invention as applied to a easement type window. As therein illustrated, there is provided a window structure 335 form-ed of a window frame 336 and an operable sash 333. The window frame 336 is formed of interconnected vertical, head and sill frame members 341, 342, 343, and 344i. The operable sash 338 is formed of vertical, upper and lower sash members 350, 351, 352, and 353. The sash 333 is provided entirely around the perimeter of its inner edge with an inner seal 372, and is provided along its outer vertical edge with an outer seal 375, and along its outer upper edge with an outer seal 377. Accordingly, there is formed entirely around the sash 338 a clearance space 378. In accordance with the present invention, the clearance space 378 communicates with the outside atmosphere through an elongated drainage channel or weep hole 381 formed between the upper outer edge 344e of the frame member 344 and a downwardly and outwardly extending water directing lip 353a formed on the sash member 353. Because of the size of the drainage slots 381, a water membrane will not form across the slot and accordingly water cannot be sucked into the clearance space 378 and around the inner seal 272 by vacuum conditions on the inside of the building wall.

From the above detailed description of the present invention, it will be seen that in a window structure of the type provided with operating sash and with transversely spaced inner and outer Seals between the operating sash and the frame, that by providing weep or drainage means between the outer surface of the window structure and the space between the sash and the frame, leakage of air around the inner seal will not cause water to be sucked around the sash through the window. It has heretofore been thought that such occasional seepage of water should be prevented by providing better seals. However, it is diicult commercially to provide adequate seals to avoid entirely the leakage of air, and where the weep holes communicating from the exterior of the wall to the space between the sash and the frame are so small that the cohesion of the water will form a liquid membrane across atenerse g3 u the weep holes and block the weep holes, vacuum conditions on the inside surface of the wall may cause seepage of water around the sash. Unexpectedly, it has been found according to the present invention that such undesirable seepage may be prevented by providing weep holes sufficiently large so that a liquid membrane cannot be formed across them. In a particular embodiment of the present invention illustrated, the weep means consist of a drainage slot approximately 1a-inch wide and extending entirely across the lower edge of the window.

although the present invention has been described by reference to only a single embodiment thereof, it will be apparent that numerous other modiiications and embodiments may be devised by those skilled in the art, and it is intended by the appended claims to cover all such and embodiments which will fall within the tru-e spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. An operating window assembly comprising a frame deiining a sash opening and formed of an upper and a lower horizontal frame member and a pair of vertical side frame members interconnecting said horizontal frame members, each of said members having a cross section with a rst transverse leg extending edgewise, and inner and outer iiange legs extending generally normal to the transverse leg; a sash portion in said opening operatively associated with said frame and including a sash frame formed of an upper and a lower horizontal sash member and a pair of vertical side sash members interconnecting said horizontal sash members, each of said sash members having a rst transverse leg extending edgewise and at least one flange leg extending generally normal thereto; sealing means operatively positioned between said inner legs and associated ones of said legs of said sash members for forming an inner seal extending entirely around the inner perimeter of said opening; and sealing means operatively positioned between the outer legs of at least said vertical side frame members and associated ones of said legs of said vertical side sash members for forming an outer seal extending at least along the outer vertical perimeter of said opening forming a downwardly and outwardly projecting lip on the bottom of the lower sash member extending below the upper surface of the lower frame member and spaced outwardly from the outer surface of said frame member to define a slot therebetween, drainage means from the space between the inner and outer perimeter of said opening to the exterior of said window sufficiently large to equalize the air pressure in said space with the air pressure on the exterior of said window.

2. An operating window assembly as set forth in claim l wherein the upper outer surface of said lower frame member is provided with an inwardly projecting chamfer and wherein said drainage means is defined between said lip and the chamfered portion of said lower frame member.

References Cited by the Examiner FOREIGN PATENTS 3/43 France. 10/50 Germany. 

1. AN OPERATING WINDOW ASSEMBLY COMPRISING A FRAME DEFINING A SASH OPENING AND FORMED OF AN UPPER AND A LOWER HORIZONTAL FRAME MEMBER AND A PAIR OF VERTICAL SIDE FRAME MEMBER INTERCONNECTING SAID HORIZONTAL FRAME MEMBERS, EACH OF SAID MEMBERS HAVING A CROSS SECTION WITH A FIRST TRANSVERSE LEG EXTENDING EDGEWISE, AND INNER AND OUTER FLANGE LEGS EXTENDING GENERALLY NORMAL TO THE TRANSVERSE LEG; A SASH PORTION IN SAID OPENING OPERATIVELY ASSOCIATED WITH SAID FRAME AND INCLUDING A SASH FRAME FORMED OF AN UPPER AND A LOWER HORIZONTAL SASH MEMBER AND A PAIR OF VERTICAL SIDE SASH MEMBERS INTERCONNECTING SAID HORIZONTAL SASH MEMBERS, EACH OF SAID SASH MEMBERS HAVING A FIRST TRANSVERSE LEG EXTENDING EDGEWISE AND AT LEAST ONE FLANGE LEG EXTENDING GENERALLY NORMAL THERETO; SEALING MEANS OPERATIVELY POSITIONED BETWEEN SAID INNER LEGS AND ASSOCIATED ONES OF SAID LEGS OF SAID SASH MEMBERS FOR FORMING AN INNER SEAL EXTENDING ENTIRELY AROUND THE INNER PERIMETER OF SAID OPENING; AND SEALING MEANS OPERATIVELY POSITIONED BETWEEN THE OUTER LEGS AT LEAST SAID VERTICAL SIDE FRAME MEMBERS AND ASSOCIATED ONES OF SAID LEGS OF SAID VERTICAL SIDE SASH MEMBERS FOR FORMING AN OUTER SEAL EXTENDING AT LEAST ALONG THE OUTER VERTICAL PERIMETER OF SAID OPENING FORMING A DOWNWARDLY AND OUTWARDLY PROJECTING LIP ON TE BOTTOM OF THE LOWER SASH MEMBER EXTENDING BELOW THE UPPER SURFACE OF THE LOWER FRAME MEMBER AND SPACED OUTWARDLY FROM THE OUTER SURFACE OF SAID FRAME MEMBER TO DEFINE A SLOT THEREBETWEEN, DRAINAGE MEANS FROM THE SPACE BETWEEN THE INNER AND OUTER PERIMETER OF SAID OPENING TO THE EXTERIOR OF SAID WINDOW SUFFICIENTLY LARGE TO EQUALIZE THE AIR PRESSURE IN SAID SPACE WITH THE AIR PRESSURE ON THE EXTERIOR OF SAID WINDOW. 